1. Field of the Invention
This invention relates to surgical methods and apparatus in general, and more particularly to surgical methods and apparatus for fusing sacroiliac joints.
2. Description of the Related Art
Lower back pain is a common ailment among the population and results in pain and suffering as well as loss of work time. Effective treatments for lower back pain will alleviate considerable patient suffering and provide economic benefits by reducing employee absenteeism. Until recently, many complaints of lower back pain and leg pain have been attributed to herniated discs or other injuries to the spinal column. However, extensive therapy and treatment has often been unsuccessful in alleviating such pain. Recently, it has been found that some of this lower back and leg pain can be attributed to symptomatic sacroiliac joint dysfunction or instability.
The sacroiliac joint is located at the juncture of the ilium, the upper bone of the pelvis, commonly called the hip bone, and the sacrum at the base of the lumbar spine, where it connects with the L5 vertebra. The function of the sacroiliac joint is the transmission of forces from the spine to the lower extremities and vice-versa. The joint is supported by a range of ligaments, including the sacroiliac ligament at the base of the joint and the anterior sacroiliac ligament at the top of the joint.
The sacroiliac joint has a limited range of motion. Nutation, the relative movement between the sacrum and ilium, is typically one to two degrees. Despite the limited range of motion, a patient's sacroiliac joint can become damaged resulting in hypermobility of the joint. Hypermobility is very difficult to diagnose due to the small range of motion. Therefore, lower back pain or leg pain caused by sacroiliac joint dysfunction, e.g. degenerative sacroiliitis, inflammatory sacroiliitis, iatrogenic instability of the sacroiliac joint, osteitis condensans ilii, or traumatic fracture dislocation of the pelvis, often goes misdiagnosed or undiagnosed.
In patients where sacroiliac joint pain is unresponsive to non-operative treatments, e.g. medication, physical therapy, chiropractic care and steroid injections, surgical stabilization is prescribed. Fusion is a surgical treatment to relieve pain generated from joint dysfunction.
Accordingly, it is a general objective of this invention to provide a method to deliver a device for correcting symptomatic sacroiliac joint dysfunction or instability, for enhancing stability for purposes of immobilizing a joint, and for fusing two opposed bone structures across the joint.